Server Chat not working

I'm an OP in my server and when ever I try and talk in the chat box or use a command I get kicked and it says "Disconnected from server. Illegal characters in chat" I can still connect to the server afterward. I have contact with the server admin and can fix the problem, but only if I get some answer from you guy's!

Thas definately a new one, I havent heard anything like that before. However, I know that you can edit the chat characters inside texture packs, could that possibly be the issue?

We don't have any texture packs and this has been going on since the beginning of the server, I've been thinking that it is something involving the admin. I know he didn't do anything but is there some code to change what is allowed and what isn't in the chat